1. Field of the Invention
The invention relates to a system and method for securing tissue to bone and more particularly to adjustable tensioning of tissue which eliminates the need for knot-tying by a user.
2. Description of the Related Art
A common injury, especially among athletes, is the complete or partial detachment of tendons, ligaments or other soft tissues from bone. Tissue detachment may occur during a fall, by overexertion, or for a variety of other reasons. Surgical intervention is often needed, particularly when tissue is completely detached from its associated bone. Currently available devices for tissue attachment include screws, staples, suture anchors and tacks. An example of a cannulated suture anchor is provided in U.S. Patent Application Publication No. 2008/0147063 by Cauldwell et al.
There are a number of suture implant systems which proclaim to be “knotless”, that is, to not require a surgeon to tie a knot during surgery. Many such systems control tension on tissue by the depth to which an anchor is driven into bone. U.S. Pat. Nos. 5,782,864 and 7,381,213 by Lizardi disclose certain types of suture anchors which capture a fixed-length loop of suture. Adjustable loop knotless anchor assemblies utilizing an anchor element inserted into a sleeve are described by Thal in U.S. Pat. Nos. 5,569,306 and 6,045,574 and in U.S. Patent Application Publication No. 2009/0138042.
Suture anchor systems with sliding knots for repairing torn or damaged tissue, especially for meniscal repair, are disclosed in U.S. Pat. No. 7,390,332 by Selvitelli et al. and are utilized in the OmniSpan™ meniscal repair system commercially available from DePuy Mitek Inc., 325 Paramount Drive, Raynham, Mass. 02767. Other suture anchor systems with sliding and locking knots for repairing tissue include U.S. Pat. No. 6,767,037 by Wenstrom, Jr.
It is therefore desirable to adjust tension on a tissue after an anchor has been fixated in bone without requiring a surgeon to tie any knots, especially during arthroscopic procedures.